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compost feasibility shows Dry AD most affordable over 20 years

Original post made by Cedric de La Beaujardiere, Barron Park, on Feb 26, 2011

The Compost Financial Feasibility Study's Preliminary Cost Analysis Summary indicates (Web Link):

YEAR-1 ...| YEAR-20 ...| 20-YEAR TOTAL | PROJECT/FINANCING OPTION
$ 68/ton ....| $118/ton ...| $71 million ..........| Truck food & yard to Gilroy, Incinerate sewage
$112/ton ...| $106/ton ...| $91 million ..........| Dry AD: private financing/private operation
$ 81/ton ....| $ 81/ton ....| $67 million ..........| Dry AD: public financing/private operation
$ 62/ton ....| $ 65/ton ....| $52 million ..........| Dry AD: City receives 30% in grants worth $12M

This shows that, over a 20 year period, the public financing of local Dry Anaerobic Digestion is $4 million more affordable than sending our wastes away. With a 30% grant, we save the rate-payers $19 million, which comes out to about $1 million a year in savings through handling our wastes locally.

Comments (13)

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Posted by Craig Laughton
a resident of College Terrace
on Feb 26, 2011 at 4:02 pm

Cedric,

If it could get done for much less than $62 per ton, would you consider that a logical choice? If that choice would also solve many more issues than anaerobic digestion does, would you consider that a good choice?

Just curious.


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Posted by Cedric de La Beaujardiere
a resident of Barron Park
on Feb 27, 2011 at 1:07 am

Cedric de La Beaujardiere is a registered user.

Hi Craig,

Thanks for your questions. Sorry in advance that my answers tend to be so long-winded.

First, for clarity, my post was an excerpt from my longer post in response to an article and its comments at Web Link. I actually posted here only because my table originally lost its formatting, so I wanted to post it somewhere else and make sure i had the column alignment right.

To get to your questions, if there was an alternative for handling all of our organics (yard trimmings, food scraps, and sewage) at much less than $62/ton (which is unlikely), yes, I would be impressed, and it would be a logical choice from a purely fiscal perspective. I would personally take a more systems-level perspective and consider whether the solution emitted more or less Green House Gases, or had other adverse impacts. So, for instance, to indefinitely continue our current sewage incineration is neither fiscally nor environmentally responsible.

In your hypothetical scenario, "if that choice would also solve many more issues than anaerobic digestion does", and if it was a realistic solution with reasonable chance of success, or a means of testing it out, then yes, I would likely think such a solution was awesome and support it.

I think a viable solution better than Anaerobic Digestion (AD) is unlikely, based on my experience serving on the city's 7-month Compost Task Force. Asked to study options for the city, we ended up recommending Dry Anaerobic Digestion because of its promise as a cost-effective and ecologically-sound solution for the city's organics waste management. So far, the independent, 3rd-party feasibility study supports this conclusion.

However, using Wet AD to digest our sewage and food together, and then compost the digestate with yard trimmings could also be viable, and members of the Palo Alto Green Energy Initiative (www.PAGreenEnergy.org) have asked that this also be considered in the feasibility study. Unlike Dry AD, Wet AD is proven for sewage, a point in its favor. On the downside, Wet AD may have more trouble with food scraps in its fluid pumps, and Wet AD uses more energy to move all that extra water around, so it may produce less net energy than Dry AD. These downsides are why the Compost Task Force recommended Dry rather than Wet AD, for the handling of food, yard, and sewage.

Regarding handling the municipal organics, the cost varies by material and treatment option (data from Web Link, in spreadsheet link labelled "Energy/Compost Preliminary Cost Estimate/Low Cost Range/Electricity", tab "2&3"):
- Yard trimmings are the cheapest and easiest to handle, the draft feasibility study shows yard-trimmings handling costing $32/ton in year-one (2015) and $49/ton in year-twenty (the increase due purely to inflation, and does not include the rising cost of fuel).
- Food scraps are more difficult to handle, and for 2015, composting is estimated at $82/ton, while sending it to GreenWaste's as yet unbuilt San Jose Dry AD facility is roughly estimated to be $99/ton.
- Sewage solids (AKA Biosolids) are currently incinerated and priced at $90/ton for 2015. Beyond inflation and rising prices for natural gas, this price should go up significantly to keep the incinerator running past it's remaining 10-year life span and through increased regulatory controls like limits on mercury emissions.
- Landfilling is not cheap either, at $53/ton for 2015 (from "Inputs" tab).

Averaged for all three inputs and their quantities, the cheapest non-local-AD and current default option for the city is $68/ton in 2015 (to compost food & yard in Gilroy, & Incinerate sewage). This goes up to $118/ton in year-20, but this is probably an under-estimate of the true cost for the reasons I stated above.


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Posted by Cedric de La Beaujardiere
a resident of Barron Park
on Feb 27, 2011 at 1:15 am

Cedric de La Beaujardiere is a registered user.

I should add that the Preliminary Green House Gas analysis shows that the local Dry AD option reduces our emissions by between 13,000 and 15,000 Metric Tons of CO2-equivalents per year. So in addition to being a net money savings, we also significantly reduce our GHG emissions.


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Posted by Craig Laughton
a resident of College Terrace
on Feb 27, 2011 at 9:26 am

"Asked to study options for the city, we ended up recommending Dry Anaerobic Digestion because of its promise as a cost-effective and ecologically-sound solution for the city's organics waste management. So far, the independent, 3rd-party feasibility study supports this conclusion."

Cedric,

Could you please guide me to where your committee studied plasma arc thermolytic destruction? Plasma arc in not incineration, and it is not combustion. It destroys or contains all toxics. Its residue (slag) is a useful building material. Plasma arc must pass all CEQA standards. If the proper fuel (garbage) mix is used, it can be a net producer of electricty. And it can all be done for a much lower cost per ton, compared to any other method considered, including AD. All this can be accomplished on a much smaller industrial footprint, compared to AD.

Plasma arc is now being tested in the Salinas Valley, where the goal is to completely eliminate land fills. It is currently being used in several countries to destroy trash.


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Posted by Resident 0.1
a resident of Another Palo Alto neighborhood
on Feb 28, 2011 at 12:16 pm

We need to move our compost to a regional facility and preserve our parkland because we cannot afford to increase our use of water. The financial burden of this facility (all costs, including water) are not in scale with the size of our community. The only reason to build this facility on parkland is because it will allow further dense development in Palo Alto, something else we cannot afford. If we continue to build, we will use more water and need new and larger infrastructure to support this development. We need to maintain our current buildings and housing and re-purpose them.

California faces enormous challenges as it struggles to adapt its water management system to 21st-century conditions. The state's population continues to grow and to urbanize, increasing demands for urban water supply, reliable water quality, and flood protection. At the same time, the state's economy no longer depends as directly on water to generate wealth: agriculture, which still consumes the lion's share of water, represents a small fraction of overall employment and economic output, and manufacturing accounts for only a small fraction of total water use. All this is taking place as California faces the uncertainties of a changing climate—and as environmental concerns take greater precedence than they have in the past, affecting critical decisions in water management. Web Link


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Posted by Craig Laughton
a resident of College Terrace
on Feb 28, 2011 at 1:06 pm

"we cannot afford to increase our use of water. The financial burden of this facility (all costs, including water) are not in scale with the size of our community"

Resident,

Please explain your statement, if you consider plasma arc, instead of anaerobic digestion.

Thanks.

Craig Laughton
Harvard St.
Palo Alto


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Posted by Cedric de La Beaujardiere
a resident of Barron Park
on Mar 1, 2011 at 1:28 am

Cedric de La Beaujardiere is a registered user.

While I agree with the importance of conserving water, I think neither Wet or Dry AD nor Plasma Arc consume much water. The plasma arc seeks to get the material as dry as possible, because it needs to be heated to high temperatures to release energy and you don't want to waste energy turning water into steam. In the Wet AD, the water comes from the sewage pipes. In the Dry AD system, water is recirculated repeatedly through the system in a closed loop. It likely uses less water than, say, municipal-scale windrow composting (which is Palo Alto's current practice for yard trimmings), in which large long rows of compost need to be kept moist, and lose water through evaporation. Salt content permitting, the city would probably seek to provide any extra water needed by the Dry AD system with recycled water from the sewage treatment plant.

So, if anything, your concern for water conservation should lead you to support such a facility. In terms of money, as I said initially, the draft feasibility study indicates publicly-financed Dry AD saves the city $4M over the 20-year planning horizon.

In regards to Plasma Arc, we did look into it in the Compost Task Force. Early in the process we decided to focus on more well-established technologies, in part because few if any companies responded for our requests for information, and overall there was insufficient data for us to draw upon to make reliable conclusions about some of the newer technologies, such as Plasma Arc and Biochar, both of which otherwise initially looked promising. You can see the records of the Compost Task Force and our final recommendations at Web Link

Note that the initiative currently being circulated does not prescribe a specific technology for converting our organic wastes to energy and compost. It merely puts it to a vote to makes the 10-acres of land available to the city for that purpose, and the Council would make the decisions about what type of facility, if any, to build.


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Posted by Craig Laughton
a resident of College Terrace
on Mar 1, 2011 at 6:49 pm

Cedric,

Please look at your own reference: Web Link

Plasma arc is superior to anaerobic digestion (AD)on a number of levels. Your point that plasma arc is not commerical in this country is also true about AD, based on your 2008 data.

However, plasma arc is not limited to organic vegetative wastes. It can handle almost ALL of the municipal waste stream, in fact it thrives on the wastes that AD cannot handle (e.g. used tires). Plasma arc also destroys or stablizies organic and inorganic toxic wastes, while AD simply redistributes them into our neighborhoods.

AD is not a rational solution to our muncipal waste stream, Cedric. I would like to know who, on your committee, made the case for plasma arc. Frankly, I don't think anyone did, because there was an agenda to promote AD. Am I right, Cedric?


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Posted by True Costs
a resident of Another Palo Alto neighborhood
on Mar 2, 2011 at 11:21 am

> With a 30% grant, we save the rate-payers $19 million

And where does the money come from for a "30% grant"? If not the "taxpayer", then whom?

Total cost is total cost. This sort of thinking is how we've gotten to a $200T debt/entitlement obligation in this country. Unless every dollar is on the table, including the finance costs for any "grants", or bonds that are sold to pay for capital equipment .. then these estimated costs are not accurate, and may rise to the level of fraud.


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Posted by Cedric de La Beaujardiere
a resident of Barron Park
on Mar 2, 2011 at 7:51 pm

Cedric de La Beaujardiere is a registered user.

@True Costs:
Yes, grants usually (but not always) come from the government and thus from taxpayers. But to the extent that these entities are supplying grants in any case, it makes fiscal sense for the city to apply for these grants and get some of that action. It is essentially a means for the state or national taxpayers as a whole to invest in Palo Alto, and to invest in clean energy, in reduced GHGs, and in community self-reliance.

The feasibility study DOES include the debt financing costs in the public financing option. Even with paying off a bond, the public financing of the Dry AD STILL saves the city and ratepayers $4 million over 20 years, compared to incinerating the sewage and sending our yard and food wastes to Gilroy (which is the city's current default course of action).

If the city were to lend itself the money to build the facility, such as by borrowing from the ~$60 million in the Calaveras fund, then the utilities/ratepayers would repay the city's own lending fund with interest, and all that interest on the debt would come back to the city itself instead of to random bond holders. The attractiveness of this strategy would depend in part on the Calaveras fund's current investment returns compared to the bond repayment interest.

.

@Craig:
Our Task Force did not have a "Plasm Arc Evangelist", and perhaps if it did, who knows it might have ended up recommending that instead. As it was, we split into three groups to investigate different types of technologies, to reach out to companies and seek infomation, to do research on our own, and to report back to the larger group. It was difficult to get info from Plasma Arc vendors, I don't recall that we got any response from them.

Wet AD is commonly used in the US and around the world.
Dry AD is used in Europe but not yet in the US, but it has enough history that we felt comfortable recommending it, especially as it handles "dry" inputs like food and leaves much better than wet AD.

There was no one on the task force with "an agenda to promote AD." It was only after months of work, study, and debate together (all of us as volunteers from the community giving of our evenings every other week or more) that we settled on Dry AD. There were some agendas, but not around particular technologies. One person's agenda was to prevent any use of the Landfill/Byxbee park, and that person joined in the unanimous support of the Dry AD on the corner of the Airport site because it was a local solution that was not on the park. My own agenda was to try to find a systemically optimal solution which maximized the benefits to the community and minimized the impacts. Early on I advocated for traditional composting distributed throughout the city's parks, to compost on site the trimmings from that park and from the surrounding residences. People could come and get a local source of compost to bring back to their gardens, see one-on-one how "wastes" are converted to resources. However, it became clear that such a solution was not meeting the city's needs, would not benefit from the economies of scale of a single operation, and it went against the Council's direction to the Task Force to consider parkland as a last resort.


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Posted by Craig Laughton
a resident of College Terrace
on Mar 3, 2011 at 8:44 am

"It was difficult to get info from Plasma Arc vendors, I don't recall that we got any response from them."

Cedric,

That is very curious. A quick look at the trade magazines in waste management indicates that Plasa Arc companies are very eager to demonstrate their technology and effectiveness. The general feeling appears to be that once the first commercial plant goes into action, it will quickly be accepted, then the floodgates will open. Which companies were contacted?

It is interesting that the Salinas Valley Solid Waste Authority has chosen Plasma Arc over anaerobic digestion.


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Posted by Cedric de La Beaujardiere
a resident of Barron Park
on Mar 3, 2011 at 9:56 am

Cedric de La Beaujardiere is a registered user.

Craig,

I can't recall off hand which companies were contacted (this was about mid 2009). I think one of the reasons that we didn't get much response from companies in general is that it wasn't an official city Request For Information (RFI) but was essentially private individuals contacting the companies, on behalf of the Compost Task Force. What's more, there wasn't a particular site yet to provide hard parameters for an estimate.

I did look again at the earlier ARI study you asked me to look at, and it seems to indicate that Plasma Arc can get more energy than AD. But I think that depends on the fuel mix (like accepting old tires, etc), and I'm not sure how Plasma Arc would compare to AD on the same yard/food/sewage mix. I think you're advocating for setting all MSW to the Plasma Arc, but then you start getting into what the public, city, and regulator agencies will accept, and also whether there's room on 10 acres to do it. You'd have to convince Council or staff to look at that, but realistically I wouldn't expect them to launch another feasibility study on yet more options, it was close enough just to get the current study approved, and that was with strong public support.

There will be another public meeting to report and get feedback on the preliminary analysis on Green House Gas, as well as to finish up on the financial analysis which was apparently cut short when the 2/23 meeting went too far over time.

Energy/Compost Interested Parties:

Many thanks to those of you attending our February 23rd meeting on the Preliminary Analysis (see details below). Because we ran out of time, we are scheduling a follow-up meeting as follows:

Date March 9, 2011
Time 7:00 to 9:00 pm
Place Palo Alto Art Center " Auditorium
1313 Newell Road
Palo Alto

We'll finish the discussion on costs and then discuss the Greenhous Gas analysis.


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Posted by Craig Laughton
a resident of College Terrace
on Mar 3, 2011 at 2:08 pm

Cedric,

Thank you for a rather complete response to my question. I appreciate your honesty, and forthrightness. It is refreshing.

Essentially, the green agenda in Palo Alto is driven by political limitations and restrictions. I get that. The question I have is why is it not driven by a progressive, instead of a regressive agenda? Why is it that the Salinas Valley is so much more progressive than Palo Alto? Remember, they want to ELIMINATE land fills, not just push them out to other people, especially people of color, and not to distribute the toxic residues all over our front lawns and backyard gardens. I don't get it...how did Palo Alto come to such a politically reactionary position?


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